Study of the Isomeric State in $^{16}$N Using the $^{16}$N$^{g,m}$($d$,$^3$He) Reaction

TL;DR

This study investigates the isomeric state in $^{16}$N using a ($d$,$^3$He) reaction in inverse kinematics, revealing it as an excited neutron-halo state through experimental measurements and theoretical modeling.

Contribution

It provides the first direct comparison of spectroscopic factors for the ground and isomeric states of $^{16}$N using inverse kinematics and DWBA analysis.

Findings

Isomeric state of $^{16}$N is an excited neutron-halo state.

Experimental data supports weak-binding effects modeled by Woods-Saxon potential.

Simultaneous measurement reduces systematic uncertainties.

Abstract

The isomeric state of $^{16}$N was studied using the $^{16}$N$^{g,m}$($d$,$^3$He)~proton-removal reactions at \mbox{11.8~MeV/$u$} in inverse kinematics. The $^{16}$N beam, of which 24% was in the isomeric state, was produced using the ATLAS in-fight facility and delivered to the HELIOS spectrometer, which was used to analyze the $^{3}$He ions from the ($d$,$^{3}$He) reactions. The simultaneous measurement of reactions on both the ground and isomeric states, reduced the systematic uncertainties from the experiment and in the analysis. A direct and reliable comparison of the relative spectroscopic factors was made based on a Distorted-Wave Born Approximation approach. The experimental results suggest that the isomeric state of $^{16}$N is an excited neutron-halo state. The results can be understood through calculations using a Woods-Saxon potential model, which captures the effects of weak-binding.